Outboard motor water inlet structure



A118- 19, 1958 E. c. KIKHAEFER 2,847,967

A ouTBoARD MOTOR WATER INLET STRUCTURE:

Filed May 18, 1956 INVENTOR. EMHZ? K/EKHAFEP BY Y United States Patent CM' OUTBOARD MOTOR WATER INLET STRUCTURE Elmer C. Kiekhaefer, Cedarburg,Wis.

Application May 18, 1956, Serial No. 585,849

1 Claim. (Cl. 115-18) This invention relates generally to outboardmotors and more specifically to an improved cooling water inlet meansfor an outboard motor.

Water cooled outboard motors are normally provided with a water inletstructure that necessitates submerging the lower unit containing thepropeller shaft and trans-l mission gears in the water in order toprovide adequate engine cooling. A disadvantage of this type ofconstruction where the motor is mounted on a transom of a boat forpropelling the boat through the water, is that the lower unit in theoperation of the outboard motor oifers a large resistance to movement ofthe outboard motor through the water resulting in decreased availablepropeller thrust for propelling the boat. Applicants improved coolingwater inlet means eliminates this disadvantage in theV prior art andoffers additional advantages to be explained hereinafter.

It is therefore an object of the present invention to provide animproved cooling water inlet means for an outboard motor that permitsutilization of more of the available propeller thrust for propelling aboat through the water.

Another object of the invention is the provision of a cooling waterinlet means for an outboard motor that provides the engine withsufficient cooling water under surface pitch operation conditions, thatis, where the motor is employed with the propeller partially out of thewater as shown in Fig. 1 with the blades thereof successively enteringthe Water. This surface pitch condition is obtained when the engine isset up for racing by mounting the engine at a height on the transomwhere all of one blade is out of the water. Under these conditions thegear case for the water pump may also be out of the water, as shown.

Another object of the present invention is the provision of an improvedcooling water inlet structure formed in the outboard motor skeg adaptedduring surface pitch operation of the outboard motor to counteract thetendency of the outboard motor propeller to move the boat to the rightor left depending on the direction of rotation of the propeller.

Another object of the invention is provide an improved cooling waterinlet structure that is weedless in operation.

Objects and advantages other than those set forth above will be apparentfrom the following description when read in connection with theaccompanying drawing, in which: l

Fig. 1 is a side elevation view of an outboard motor embodying theinvention and operating under surface pitch conditions with thepropeller partially `out of the water;

Fig. 2 is an enlarged fragmentary front elevation view of a portion ofthe structure shown as viewed from the left in Fig. 1;

Fig. 3 is an enlarged fragmentary side elevation view partially insection of a portion of the outboard motor shown in Fig. 1;

' 2,847,967 Patented Aug. 19,1958

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Fig. 4 is a section view taken on line 4-4 of Fig. 3; and

Fig.' 5 is an enlarged section view taken on line 5--5 of Fig. 3.

As shown in the drawings, the preferred embodiment of this invention isillustrated as applied to an outboard motor 1 having a drive shafthousing 2 supporting an engine, not shown, enclosed within a cowl 3 atone end and secured to a lower gear case housing 4 at the other end. Theoutboard motor 1 is removably secured to the transom 6 of a boat bymeans of a clamp bracket 7 and clamping screw 8, and is further pivotalabout a vertical rod 9 carried by a swivel bracket 11 for dirigiblemovement of the motor by means of a steering handle, not shown.

The gear housing 4 shown as a single piece casting is provided with astreamlined strut portion 12 at one end for securement to the driveshaft housing 2. The opposite end of the gear housing 4 is provided witha skeg 13 shown as a thin, streamlined, plate member. The skeg 13 andthe strut 12 merge to form a hollow ellipsoidal casing 14 for housing awater pump 16, propeller shaft 17 and transmission gears, not shown. Theskeg 13 is further provided with a shallow grooved out channel 18 havinga generally planar leading portion 10 smoothly merging with the leadingedge of the skeg 13 and a trailing ridge portion 15 extending generallyupwardly and rearwardly for directing Water generally upwardly throughan opening 19 formed in the casing 14 to the inlet of the water pump 16within which an impeller 21 is disposed. The impeller 21 upon rotationof the propeller shaft 17 forces water out of the water pump 16 througha conduit 23 to the engine coling system as is old in the art. Thechannel 18 upon forward motion of the outboard motor 1 acts as a scoopto direct the water into the pump casing 21. The curvature of thechannel 18 is of a configuration as shown in Fig. 4 whereby waterpassing the skeg 13 as it slices through the water develops a lateralforce thereon due to frictional pressure and turbulence on surface 18and the reduced pressure area on the opposite side of the skeg. Thisforce acts in the general direction indicated by the force vector F.This lateral force tends to move the outboard motor laterallycounteracting the lateral force F2 in which the propeller 22 rotating inthe direction shown in Fig. 2 tends to produce to move the outboardmotor 1 and rear end of the boat during surface pitch operation.

In the operation of applicants invention, the outboard motor 1 may bedisposed upon the transom 6 of a boat for surface pitch operation withonly the skeg 13 and the lower propeller blade of the outboard motorextending into the water. Upon forward movement of the motor 1 and boat,the water passing the skeg 13 is directed to the inlet of the water pumpby means of the channel 18. The lateral force developed by the wateracting against the surface of the skeg 13 tends to move the boat andmotor in a lateral direction counteracting at least in part the tendencyof the propeller 22 to move the boat and motor in the oppositedirection. This permits the operator to maintain the boat on a straightline course without pivoting the motor to the right as far as otherwiserequired about the vertical rod to counteract the lateral forcedeveloped by the propeller 22.

Although but one embodiment has been illustrated and described, it willbe apparent to those skilled in the art that Various changesandmodifications may be made therein without departing from the spiritof the invention or from the scope of the appended claim.

It is claimed and desired to secure by Letters Patent:

In a dirigible outboard motor wherein the submerged propeller or portionthereof produces a side thrust on the outboard generally requiring acompensating steering position for the outboard to eiect forward boatmovement, and wherein the motor is water cooled necessitating a constantsupply of water thereto during operation, means to assure an adequatewater supply andpto at least in part compensate said side thrust, saidmeans comprising a generally ellipsoidal streamlined lower gear casing,a downwardly extending skeg centrally and longitudinally disposedbeneath said casing, a propeller shaft disposed axially in said casingand extending rearwardly therefrom, a propeller mounted on the rear endof said shaft to drive the boat forwardly through the water, saidpropeller producing an unbalanced side thrust on said casing and skegdepending upon the location of the propeller relative to the surface ofthe water, a Water inlet port in the bottom of said casing on the sideof the skeg toward 4. which said propeller tends to thrust the casingduring such forward movement, and a water scoop channel leading upwardlyand rearwardly in said side of the skeg and to said inlet port toprovide a supply of water to said port even when the outboard is beingoperated under surface pitch conditions and to provide a side thrust inpart compensating said unbalanced propeller side thrust.

References Cited in the le of this patent UNITED STATES PATENTS1,716,962 Johnson .Tune 11, 1929 1,893,662 Smith Ian. 10, 1933 2,147,638De Port Feb. 21, 1939 2,167,533 Solomon July 25, 1939 2,616,386Kiekhaefer Nov. 4, 1952

